ELMO GS 1200 : FWD SOLENOID (FLYWHEEL DRIVE DISENGAGEMENT) no more energized

[Phil Murat]

Hello GS1200 Fans,

I observed this new problem while the rear cover was removed. When the machine is in FWD mode, the solenoid is no longer powered (no 25V DC) and no longer disengages the flywheel drive anymore.
The solenoid is located near the front foot. So here is a new fault isolation reason, especially since this solenoid does not appear in the documentation!!!

Has anyone come across this problem before ?

[Thomas Knappstein]

Hi Phil!
All the Solenoids in the GS 1200 are starting with 35V from the black and green Rectifiers which is for the Main Motor and the Fan Motor too.
When the Solenoid has plugged in he pushed a microswich and changed the Voltage to 12V for holding. This 12V came from the black Sqare Rectifier in the Middle of the Main Board. If the Microswich is defect and can´t swich to the 12V, the Solenoid will be work with 35V every time. The Coil will be burn out because it is only make for 12 V. Only for a few milliseconds when starting he becomes the 35V for strong plug in.

So you have to check the Solenoid first with an external Power supply and when it is ok, check the microswich on the Solenoid and the two Voltages in the GS 1200 came from the two Rectifier Groups on the Main Board.

[Phil Murat]

Hi Thomas,

Thanks a lot for your answer.

I have not investigated yet for this issue. I understand this solenoid is directly powered from a rectifier (nothing more between solenoid and rectifier ) correct ?

I have review GS1200 Service Guide (p99) et I have not found anything for this solenoid, only found :

SL301 = Thread
SL302 = Heat Proof Glass
SL303 = Head Presser
SL304 = Pinch Roller

Should you have anything more from your side in an other documentation ?

You are right , what you explained concerning 35V then 12 V appears on page 100 of document.

To be continue........

[Thomas Knappstein]

Hi Phil!
I´m so sorry, but I forgott that there are two Transistors for swiching the Solenoid. There are four of them right of the flying Wheel on the main Board. Please have a look into the service Manual. there you can see how this is working.

[Thomas Knappstein]

I think it is SL304 Pinch Roller.

[Phil Murat]

Hi Thomas,

Thanks for your answers !!!

Now , I have observed that both Solenoids for "Head Pressers" and "Pinch roller" are not working anymore...............

Moreover, I made a big mistake when I was measuring voltage with probes : one probe made a short circuit between ground and a terminal on the small board fitted on big solenoid next to front feet (a beautifull electric arc !) 🙄
That could be a bit more chalenging now 😉

To be continued